The present invention relates generally to an upholstered cushion article. More particularly, the invention relates to a structure and method for preparing an upholstered multi-density cushion article without having to use a conventional mold during the manufacturing process.
Well established methods of manufacturing upholstered cushion articles have involved cutting the covering material in accordance with a chosen pattern, sewing the material and then mounting the material on a cushion. This method of manufacture, however, usually involves high labor costs associated with the cutting and sewing operations.
In order to reduce the labor costs associated with the traditional manufacturing method, a pour-in-place, or foam-in-cover, technology was developed (see, for example, "New Methods for the Production of Comfortable Car Seats", K. Bukowski and W. Schoberth, S.A.E. Technical Paper Series, National Congress and Exhibition, Detroit, Mich., Feb.-Mar., 1985). This method is usable for either vinyl or laminated fabric cover materials. The cover material is usually first heated and then drawn into a cold mold by a vacuum applied between the mold and the cover material. As the covered material cools, it assumes the shape of the mold. A foamable material is then introduced into the mold to form the foam cushion portion of the cushion article. This technology enables relatively rapid and efficient manufacture of cushion articles, but requires the use of rather expensive capital equipment.
Other techniques exist for improving the manufacturing process, such as the method of injecting a cream foam into a preformed, porous bun. This method is a reliable method of preparing finished cushion articles having widely different densities and compressibilities. However, this approach of preparing different density cushion articles requires a relatively large number of individualized process steps which causes the cost of production to be quite high. In another approach, different density cushion articles are prepared independently, and the articles are bonded or glued together. Again, however, a relatively large number of steps are required to achieve a finished multi-density cushion article, and consequently the manufacturing cost is relatively high. In order to reduce the number of production steps, equipment has been developed which deposits different density foam at different locations, thus providing a multi-density cushion article in one step (see, U.S. Pat. No. 4,379,859). Unfortunately, this technology does not produce a well defined boundary between the different density regions. Futhermore, this method requires a large amount of capital for the purchase and maintenance of the equipment. Consequently, the increased capital and operating costs make such preparation methods uneconomical for most manufacturers of cushion articles.